Preheat oven to 180ºC.
Grease and line the base and sides of a 20cm round loose bottom cake tin.
Beat butter and castor sugar until pale and fluffy. Beat in the eggs one at a time (it will look a bit curdled). Gently fold in lemon zest.
Add the salt to the flour and add to the egg mixture, alternating with the yoghurt. Spoon the mixture into the prepared tin.
Arrange the apple slices on top of the cake and sprinkle lightly with castor sugar. Bake for 45 – 55 minutes until golden brown and a skewer inserted into the centre of the cake comes out clean.
While the cake bakes, put all the sauce ingredients in a pan and let it warm until the butter has melted.
Remove cake from oven but leave it in the tin. Using a fine skewer, pierce the cake all over and spoon the warm sauce over the cake so it soaks evenly.
Once cooled, remove from the tin and serve.Recipe reprinted with permission of HeinStirred. To see more recipes, click here.